The invention relates to a fuel tank attachment, a fuel tank, in particular, a motor-vehicle fuel tank, and to a method for producing a fuel tank attachment.
US 2006 099 365 A1 discloses an attachment that has a first and a second region. Both the first and second regions have the same non-miscible blend of a fuel-resistant ethylene vinyl alcohol copolymer, a non-fuel-resistant HDPE, and an HDPE-based grafted compatibilizer.
EP 1 108 653 A2 discloses a fuel tank comprising a container region composed of HDPE and an attachment composed of a non-miscible blend of fuel-resistant plastic, e.g., polyamide, HDPE, and a compatibilizer.
US 2003/0124281 A1 also discloses an attachment. It has an injection-molded connection nipple composed of a glass-filled polyamide that is attached to a coextruded film composed of a polyamide, a functionalized polyethylene, and a high-density polyethylene. The element thus created is welded onto a single-layer or multi-layer tank composed primarily of HDPE. This approach allows only a fluid-tight or vapor-conducting system to be created that has a joining zone composed of a coextruded multi-layer structure.
DE 195 35 413 C1 discloses a component that is composed of a tubular thermoplastic body that has a stepped annular body at one end and a retaining ridge at the opposite end. Opposite the inner diameter of the body, a circular ring with a projection is molded on, offset by the wall thickness of the body. An intermediate layer functioning as an adhesion promoter is incorporated in the stepped annular body. Under this, an annular body element is molded on enclosing the ring with the projection. When heated, the annular body element, intermediate layer, and circular ring of the tubular body are joined to each other, in addition to the mechanical connection that is effected by the circular projection.
Since this type of attachment does not withstand swelling by the plastics, the plastic of the annular body element, according to DE 100 62 997 A1, is cross-linked in such a way that a chemical bond is created between the plastics of both parts by means of bridging across the interface between the parts. At its end pointing towards the tank, the tubular body is divided into an inner tubular body and an outer tubular body.
WO 2008/113821 A1, which the invention uses as a starting point as the closest prior art, discloses a fuel tank attachment that has a first region that is composed of a first plastic, and a second region, wherein the second region has a blend of the first plastic and a second plastic, wherein the first and second regions are integrally bonded together. The fact that the second region is composed of a blend provides an integral bond between the fuel tank attachment and an outer wall of a fuel tank, the outer wall being composed of the second plastic. The disadvantageous aspect in particular here is the technical cost of fabrication to produce this type of fuel tank attachment, since this has two different regions that are composed of different plastics or plastic blends which have to be integrally bonded to each other so as to first provide the possibility of creating the integral bond with the fuel tank.